The usefulness of antimicrobial soap products has recently been under scrutiny. For example, it has been found that the antibacterial/antiviral efficacy of triclosan-based soaps against E. coli, or mixed bacterial/viral cultures, is much lower, if anything at all, than the efficacy of 70% ethanol or 10% bleach (Aiello et al., “Consumer antibacterial soaps: effective or just risky?” Clin Infect Dis. 2007, 45 Sup. 2:S137-47; Aiello et al., “Relationship between triclosan and susceptibilities of bacteria isolated from hands in the community,” Antimicrob Agent Chemother 2004; 48:2973-9; Steinmann et al., “Comparison of virucidal activity of alcohol-based hand sanitizers versus antimicrobial hand soaps in vitro and in vivo,” J Hosp Infect. 2012, 82(4):277-80). Moreover, by a recent statement of Colleen Roger, PhD, lead microbiologist at the FDA, the FDA raised the question about the efficacy of triclosan-based cosmetic and sanitizing products: “In fact, there currently is no evidence that over-the-counter (OTC) antibacterial soap products are any more effective in preventing illness than washing with plain water.” Henceforth, manufacturers of antibacterial products like hand soap or body wash will be required to prove the efficacy of their products (announced by the FDA on Dec. 6, 2013).
Further, in order for triclosan to be even somewhat effective, at least twenty minutes of contact time with the surface being sanitized is required (Wisplinghoff et al., “Resistance to disinfectants in epidemiologically defined clinical isolates of Acinetobacter baumannii,” J Hosp Infect 2007, 66(2):174-81). Otherwise, triclosan provides nearly zero efficacy. Clearly, washing hands for at least twenty minutes is impractical. And if triclosan is diluted with water, its efficacy is further reduced. Typically, soaps are diluted with water in order to have a foaming effect in the hand washing process.
Also, there are several known side effects of triclosan use. For example, triclosan is known to stimulate bacterial resistance to dangerous bacterial strains such as Methicillin-resistant Staphylococcus aureus (MRSA) or P. aeroginosa (Benerjee et al., “Comparative analysis of newly introduced disinfectants in hospitals in India: An important aspect of infection control policy,” International Journal of Infection Control, 2013, 9, 2-5; Brenwald et al., “Triclosan resistance in methicillin-resistant Staphylococus aureus (MRSA),” J. Hosp. Infect. 2003, 55(2):141-4; Chuanchuen et al., “High-level triclosan resistance in Pseudomonas aeruginosa is solely a result of efflux,” Am. J. Infect. Control., 2003, 31(2):124-7; Fiss et al., “Formation of chloroform and other chlorinated byproducts by chlorination of triclosan-containing antibacterial products,” Environ. Sci. Technol. 2007, 41(7):2387-94).
Furthermore, recent data show that triclosan is responsible for altering hormone regulation, weakening the immune system, unhealthy weight loss, uncontrolled cell growth and causing allergic sensitization in children (Cherednichenko et al., “Triclosan impairs excitation-contraction coupling and Ca2+ dynamics in striated muscle,” Proc Natl Acad Sci USA. 2012, 109(35):14158-63; Bertelsen et al., “Triclosan exposure and allergic sensitization in Norwegian children,” Allergy 2013, 68(1):84-91). Also detectable levels of triclosan have been found in blood, urine and breast milk (Allmur, Mats. “Triclosan in plasma and milk from Swedish nursing mothers and their exposure via personal care products,” 2006. Sci. Total Environ., 372, 1:87-93).
Benzalkonium chloride is another product found in some of hand soaps; it purports 99.9% bacterial kill. The compound is known as a common preservative, but has serious side effects. For example, enrichment of benzalkonium chloride gives rise to resistant bacterial species as well as conjunctive toxicity and immunoinflammatory reactions (Rasmussen et al., “Benzalkonium chloride and Glaukoma,” J. Ocul. Pharmacol. Ther. 2013; Tandukar et al., “Long-term exposure to Benzalkonium Chloride disinfectant results in change of microbial community structure and increased antimicrobial resistance,” 2013, Envron. Sci. Technol. 47(17):9730-8; Kuda et al., “Resistance to benzalkonium chloride of bacteria dried with food elements on stainless steel surface,” 2008, LWT-Food Sci Technol, 41, 988-993).
There is clearly a need for an antimicrobial soap that is effective in killing microbes but does not have deleterious side effects.